I would like to make it so that a certain quantity of a product has the same exact shipping price and when the quantity goes over the threshold, the shipping price doubles.
For example, for product X, the shipping price is Y for quantities 1-12. For 13-24, the shipping price is Yx2, for 25-36, it's Yx3 and so on.
The reason for this is the manufacturer considers anything in a box of 12 (whether it actually has 12 or not in there) is a certain "weight" (the weight is how much it would be if it was 12 products, even if there is less than 12 products in there).
To make thing a little more difficult, the shipping is not a flat rate throughout the website. Each product has a different weight and needs to be calculated differently from one another.
I hope this makes sense. It's very hard to explain over text. I'm new to Magento so I have no idea how to start looking for a solution.